In 1999, the FAO Environment and Natural Resources Service published
some global climate grids, a map showing the Koeppen climate
classification next to various derived products such as the agroclimatic
production potential according to Lieth
(details).
Regardless of several inconsistencies which users soon discovered,
the maps turned out to be very popular and were widely copied, pasted
into other web pages as well as linked to.

We are presenting below some updated maps based on improved recent
global climate grids (click here for the source of the
original data)
and a more consistent methodology
([pdf]
with an overview of the definition of Koeppen classes). Results of a recent recalculation
of climatic net primary production can be found
here. The image below
shows average Koeppen climate for the period 1951-2000 based on the
CRU and VASClimO datasets. Click
here
to download a larger version of the map. A very nice map can also be downloaded
here from the Department
of Natural Sciences at the University of Veterinary Medicine, Vienna.

The new maps are presented for two time periods, to allow users to
assess changes that have taken place recently. For instance, the map
below shows in red all the areas where the climate has changed (3rd
level of Koeppen classification) between the two reference periods
from 1951 to 1975 and 1976 to 2000.

A larger version as well as a georeferenced variant of the image
in IDA/WinDisp format can be downloaded by clicking
here.

Methodology

The new globally gridded Koeppen climatologies are based on
climatological observations rasterized to grids of 0.5°x0.5°
degrees. They cover 4 different periods and are based on 3 different
precipitation datasets. This leads to a total number of 12
rasterized Koeppen climatologies.

Mean annual cycles of temperature are always taken from the Climatic
Research Unit (CRU, Mitchell and Jones, 2005). Precipitation is taken
from 3 different sources:

Precipitation data set of CRU based on about 10,000 station records
(Mitchel and Jones, 2005),

GPCC
Full data, based on all time series fragments available to GPCC (>40,000
stations, Rudolf et al., 2005),

GPCC VASClimO data,
based on 9,343 stations that provide at least 90% coverage within 1951-2000
(Beck, Grieser and Rudolf, 2005).

The 4 different periods are:

1951 – 2000 (all),

1961 – 1990 (norm),

1951 – 1975 (early),

1976 – 2000 (late).

All different datasets are converted to the same 0.5°x0.5° grid,
which results from USGS gtopo30. Antarctica and Greenland are left out
due to lack of data.

For the users convenience data are provided in several formats: comma
separated values, IDA/Windisp geo-referenced grids, and GeoTIFF, which
can be viewed either as images (TIFF) or georeferenced grids. For
both IDA/WinDisp and GeoTIFF, the Koeppen classes, that are identified
as strings of letters (e.f. E, or Af, or Cfa) have to be recoded as
numbers. The following coding system (“byte representation”) was adopted:

TROPICAL

COLD

Af

13

Dfa

162

Am

23

Dfb

165

As

33

Dfc

168

Aw

43

Dfd

170

Dwa

172

DRY

Dwb

175

BSk

63

Dwc

178

BSh

73

Dwd

180

BWk

83

Dsa

182

BWh

93

Dsb

185

Dsc

188

TEMPERATE

Dsd

190

Cfa

112

Cfb

115

Cfc

118

POLAR

Cwa

122

ET

213

Cwb

125

EF

223

Cwc

128

Csa

132

Other

Csb

135

Sea

254

Csc

138

Missing

255

The coding is such that A climates cover the range from 13 to 43,
Cf ranges from 112 to 118 etc. Oceans and large freshwater bodies are
coded as 254, while land areas that were assigned no climate values
(for instance very small islands) are indicated with a value of 255.

Downloads as comma separated values (csv):

For each data source, the file contains a list of comma separated values
(csv) ready for the use with Microsoft Excel. There are of 63,660 lines,
each corresponding to a grid point over land. The five columns (data
items on a line) are the gridpoint number, the longitude (in 0.01°),
the latitude (in 0.01°), the fraction (in %) of the area of the
0.5°x0.5° pixel covered by land, and the Koeppen class using the
standard 3-letter codes. The csv files are available zipped or unzipped.

IDA stands for Image Display and Analysis format.
These files can be easily displayed and rescaled with
Windisp.
Windisp also allows further processing of the data including the easy manipulation of
colour scales.

We provide the Koeppen maps in their original 0.5°x0.5° resolution.
Each pixel that covers a fraction of land is drawn as a whole pixel.
We furthermore resampled these maps on a 5’x5’ grid. The resulting
fine-scale images still contain the classes on a .5°x.5° grid but
the coastlines are represented more precisely.

Windisp can display the Koeppen classes up to the first, second
or third letter. This allows the maps to be displayed in full (3
letters) or medium (2 letters) accuracy or to concentrate on the
5 major classes (1 letter). The colour scales come in two flavors,
with and without an explicit byte representation. The resulting
6 colour scales are available here.

In order to display the GeoTIFF files in colour with ESRI ArcView
GIS, ESRI legend files are provided for Koeppen classification up
to the
first,
second and
third
letter, respectively. A customised
legend can be created with the help of the byte code used within
the GeoTIFF files. This byte code is presented
here.
The GeoTIFF images can also be viewed using the FAO AgroMetShell software (AMS)
that can be downloaded from the
FAO-agromet FTP site.
Note that the GeoTIFF files can be viewed with the colour tables listed under
“Downloads as IDA (Windisp)” above.

Additional information

For further information on the area size covered by different
Koeppen climate classes click here.